Spacecraft Internal Charging Simulation of the Electronics Device Plastic Cases

Abstract

We have simulated an electron bulk charging of the plastic cases of electronic devices as an integral part of the spacecraft internal charging problem. The semiconductor crystal has been placed inside a spherical shell of a polymer dielectric $10^{\mathrm {-3}}$ – $10^{\vphantom {R^{l}}\mathrm {-2}}$ m thick having an intrinsic (dark) conductivity in the range from $10^{\mathrm {-16}}$ to $10^{\mathrm {-9}}\,\,\Omega ^{\mathrm {-1}}\cdot \text {m}^{\mathrm {-1}}$ . The crystal itself is a parallelepiped with sharp edges and vertices which substantially reduce an electrical strength of the case polymer. To assess this effect, we studied the field enhancement at the electrode as a function of its radius of curvature by measuring the reduction of the breakdown strength of air in a similar configuration for electrode radii $2 \times 10^{\vphantom {R^{l}}\mathrm {-5}}$ – $10^{\mathrm {-2}}$ m.